Arrangement for driving valves

Abstract

A valve drive arrangement for use in an engine having a pair of intake valves and a pair of exhaust valves for each cylinder. Each pair of intake valves are coupled to each other by a valve bridge and forced downwards simultaneously by a single rocker arm, and each pair of exhaust valves are coupled to each other by another valve bridge and forced downwards simultaneously by another single rocker arm. A contact member is rotatably provided on an upper surface of each valve bridge such that it contacts the associated rocker arm. The press center of the rocker arm to the associated contact member and center lines of the associated valves lie in a single plane. A rotation center of the associated contact member is offset from this single plane.

What is claimed is:  
     
       1. An arrangement for driving a plurality of valves of an engine, comprising: 
       at least one valve bridge for at least one pair of valves, each valve bridge coupling each pair of valves;  
       at least one rocker arm, each rocker arm being associated with each valve bridge for forcing the pair of valves coupled by the each valve bridge in a valve opening direction simultaneously; and  
       at least one contact member, each contact member being rotatably located on an upper face of each valve bridge such that it contacts the associated rocker arm, with a press center of each rocker arm to the associated contact member and center lines of the associated valves lying in a single plane, and a rotation center of the associated contact member being offset from the single plane.  
     
     
       2. The arrangement for driving a plurality of valves according to claim  1 , wherein the plurality of valves include at least one pair of intake valves and at least one pair of exhaust valves. 
     
     
       3. The arrangement for driving a plurality of valves according to claim  1 , wherein each contact member has a head and a stem extending from the head, and the stem is rotatably received in a recess formed in the associated valve bridge. 
     
     
       4. The arrangement for driving a plurality of valves according to claim  1 , wherein each rocker arm has a chip made from a wear-resistive material, and the chip contacts the associated contact member. 
     
     
       5. The arrangement for driving a plurality of valves according to claim  3 , wherein each rocker arm has a chip made from a wear-resistive material, and the chip contacts the head of the associated contact member. 
     
     
       6. The arrangement for driving a plurality of valves according to claim  3 , wherein the stem of each contact member is loosely fitted in the recess of the associated valve bridge. 
     
     
       7. The arrangement for driving a plurality of valves according to claim  3 , wherein each contact member is made from a wear-resistive material. 
     
     
       8. The arrangement for driving a plurality of valves according to claim  1 , wherein bridge guides are not provided for supporting movement of the valve bridge.